21145121530 has 64 divisors (see below), whose sum is σ = 42824920320. Its totient is φ = 7458587136.

The previous prime is 21145121443. The next prime is 21145121537. The reversal of 21145121530 is 3512154112.

It is a junction number, because it is equal to n+sod(n) for n = 21145121495 and 21145121504.

It is not an unprimeable number, because it can be changed into a prime (21145121537) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2636166 + ... + 2644174.

It is an arithmetic number, because the mean of its divisors is an integer number (669139380).

Almost surely, 2^21145121530 is an apocalyptic number.

21145121530 is an abundant number, since it is smaller than the sum of its proper divisors (21679798790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21145121530 is a wasteful number, since it uses less digits than its factorization.

21145121530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8935.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 21145121530 its reverse (3512154112), we get a palindrome (24657275642).

The spelling of 21145121530 in words is "twenty-one billion, one hundred forty-five million, one hundred twenty-one thousand, five hundred thirty".